Visual inattentionand visual field loss

NHS and Social Care Partnership Trust

Kent and Medway

Better Together

VISUAL INATTENTION

Visual inattention is a common condition associatedwith stroke. Also known as ‘unilateral spatialneglect’, or more simply as ‘neglect’, it presents asa difficulty in detecting or acting upon informationon one side of space.

People with visual inattention behave as if they donot notice or are no longer interested in eventsthat occur on one side. They may appear to ignoreothers who stand on their affected side and/ or fail tocarry out basic self-care tasks, such as washing andshaving on one side of their body.

Although visual inattention is a particularlycommon consequence of stroke, it can also occurfollowing other forms of acquired brain injury (suchas traumatic brain injury).

Hemispheres of the brain

The brain is divided into two halves, known as‘hemispheres’. The right side (hemisphere) ofthe brain controls muscles on the left side ofthe body and vice versa. It is for this reasonthat damage to one side of the brain affectsthe opposite side of the body.

The side that is affected by visual inattentionis usually opposite the brain hemispherethat has been damaged by the stroke(i.e. a patient with a right hemispherestroke will, in most cases, present withleft-sided inattention).

Visual Inattention and the rightside of the brain

Visual inattention is more common followingright hemisphere strokes: if tested within thefirst three days of their recovery, 85% ofpeople who have had a stroke in the righthemisphere of their brain will show signs ofthe disorder, compared to 65% who have hada stroke in their left hemisphere.

How does someone behave ifthey have visual inattention?People with inattention may display a rangeof behavioural symptoms, such as:

• Missing food on one side of their plate.

• Failing to attend to one side of their bodywhilst washing and dressing (e.g. shavingonly one side of their face).

• Not noticing people approaching from theiraffected side.

• Finding it difficult or impossible to read.

Drawings by patients with inattention

The zone ofinattention

Region ofbraindamagecaused bythe stroke

Prolonged visual inattention isassociated with right hemispherebrain damage

Visual inattention usually resolves within 10days. However, in approximately 10% ofcases, the syndrome persists for weeks oreven months. For some, the condition canbe permanent. People with persistinginattention are nearly always those who havehad right hemisphere brain damage.

The link between visualinattention and alertness

Many of the brain regions that are involved inhelping us to pay attention to both sides ofspace (visual attention) are also involved inhelping us to concentrate and stay alert(sustained attention).

When these brain regions (such as the frontpart of the brain - see below) are damaged,both visual and sustained attention can beaffected. It is for this reason that people withpersisting visual inattention alsofrequently present as drowsy anddistractible.

Visual inattention and fatigue

When a person has visual inattention, theirawareness of the affected side is likely tofluctuate in line with their fatigue; i.e. theirinattention will be worse when they are tiredand will improve when they are alert.

Visual inattention and awareness

The right frontal lobe of the brain plays animportant role in awareness and empathy(being able to see yourself from anotherperson’s perspective). People with inattentionoften have limited awareness of theirdifficulties. This can serve to hamper theirrecovery and limit their independencebecause it prevents them from recognisingthe need for rehabilitation.

Risks associated withvisual inattention

People withinattention may fail tonotice people orobjects approachingfrom the left. As aconsequence, theymay bump into peopleand objects on their‘neglected’ side.

People with visual inattention will often needclose observation when engaged in high riskactivities, such as cooking. It is also importantto note that inattention can re-emerge attimes when the person is particularlyfatigued, often many months after it hasapparently resolved.

General Strategies

People with visual inattention should beencouraged to engage in activities, such asreading, shaving and therapy (such asphysiotherapy) when they are most alert.

Others can help toimprove their alertnessby, for instance, askingthem to drink a colddrink before starting atask or by placing acold flannel on the backof their affected(‘neglected’) hand.

People with visual inattention should avoidparticularly important or risky activities whenthey are fatigued as their inattention is likelyto be at its worst at this time.

Individuals with visualinattention should beencouraged to movetheir affected armbefore and duringimportant tasks; insome cases, this canimprove awareness of the ‘neglected’ side.Even if movement is very limited, thistechnique may still be helpful.

ManagingDistractions

People with visualinattention are oftenhighly distractibleand find it difficult tosustain theirattention. Beforeembarking on any

important tasks, such as physiotherapyexercises, others should try to reduceenvironmental distractions and promptthe person to avoid talking.

On the Move

Prompting individualswith visual inattentionto look towards theiraffected side will haveonly a momentaryeffect and might, overtime, cause them tofeel irritated andfrustrated. Instead,they should beencouraged to trylistening to a tape recording of their ownvoice, reminding them to scan, whilst carryingout activities that are affected by theirinattention (i.e. shaving and/ or eating).

Reading

In the case of left inattention, place athick red vertical line on the left edge ofa laminated sheet. Place the sheet overbooks and magazines so that the line lieson the inside margin: prompt theindividual to find the line beforebeginning to read. This should help themto attend to the start of sentences.

REHABILITATION STRATEGIES THAT MAY BE HELPFUL FORPEOPLE WITH VISUAL INATTENTION

The Visual FieldsA person’s ‘visual field’ is the total area inwhich they can see objects on one side, whilstfocusing on a central point (see below).

Visual Field LossThe most common forms of visual field lossfollowing stroke and brain injury are‘homonymous hemianopia’ and‘quadrantanopia.’

Homonymous hemianopia(Also known as hemianopsia) is decreasedvision or blindness in half the visual field of oneor both eyes. The picture below illustrates whatsomeone with left homonymous hemianopiamight see.

Quadrantanopia(Also referred to as quadrantanopsia/quadrantic hemianopia) is decreased vision orblindness in one quarter of the visual field ofone or both eyes.Fortunately, most people learn to compensatefor visual field loss by moving their head andusing their intact visual field to scan theirenvironment.

Can people have visual field lossand visual inattention?Although people with visual inattention mayappear to be experiencing visual difficulties,they can often ‘see’ perfectly well. In contrastto someone with visual field loss, their problemsstem from an inability to self-direct theirattention to one side; they can often becomeaware of information in their ‘neglected’ fieldwhen their attention is drawn to it.Visual inattention often co-occurs with visualfield loss. As previously stated, when peoplehave visual field loss, they usually learn tocompensate by moving their head andusing their intact visual field to scan.However, when people have visual field loss andvisual inattention, their accompanying impairedawareness and poor sustained attentionundermines their ability to use compensatorystrategies, such as scanning. Inattention cantherefore worsen the impact of a visualimpairment.

Left visual field Right visual field

What someone with lefthomonymous hemianopia might see

THE DIFFERENCE BETWEEN VISUAL FIELD LOSSAND VISUAL INATTENTION

What someonewith aright upperquadrantanopiamight see

Dr Melanie GeorgeSenior Clinical NeuropsychologistKent Clinical Neuropsychology Service

www.kmpt.nhs.uk/clinicalneuropsychology

Leaflet Reference Number: KMPT.PI.leaf095 Published Date: September 2010Copyright © Kent and Medway NHS and Social Care Partnership Trust 2010

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